Teeth are typically classified as anterior or posterior. Anterior teeth are in the front of the mouth; posterior teeth are in the back of the mouth. Typically, a patient has six upper anterior teeth and six lower anterior teeth. The anterior teeth usually have a narrow incisal edge. In a patient who has a normal bite relationship, the incisal edges of the upper anterior teeth are positioned slightly further towards the front of the patient's mouth than the incisal edges of the lower anterior teeth. In this arrangement, the incisal edge of the lower anterior teeth may contact the rear-facing (or lingual) surface of the upper anterior teeth.
A patient can have as many as ten upper posterior teeth and ten lower posterior teeth, although it is quite common to have fewer (e.g., wisdom teeth are frequently removed). The posterior teeth have an occlusal surface that faces the teeth on the opposite arch and forms the biting surface.
A dental restoration is used to restore a tooth or multiple teeth. For example, a crown is a dental restoration that is used to restore a single tooth. A bridge is another example of a dental restoration. A bridge restores multiple teeth. In some circumstances, dental restorations are used to restore functionality after a tooth is damaged. In other circumstances, dental restorations are used to aesthetically improve a patient's dentition.
Generally, a dental restoration must fit harmoniously with the patient's surrounding dentition, and especially with the opposing dentition. For example, the occlusal surface (i.e., the biting surface) of a restoration should be carefully designed to avoid interfering with the closure and movement of the jaw.